import functools
import json
import os
import re
import shutil
import subprocess
import sys
from typing import Dict, Optional

import arrow
import click
import packaging
import requests

from lightning_app import __package_name__, __version__
from lightning_app.core.constants import APP_SERVER_PORT
from lightning_app.utilities.app_helpers import Logger
from lightning_app.utilities.cloud import _get_project
from lightning_app.utilities.network import LightningClient

logger = Logger(__name__)


def _format_input_env_variables(env_list: tuple) -> Dict[str, str]:
    """
    Args:
        env_list:
           List of str for the env variables, e.g. ['foo=bar', 'bla=bloz']

    Returns:
        Dict of the env variables with the following format
            key: env variable name
            value: env variable value
    """

    env_vars_dict = {}
    for env_str in env_list:
        var_parts = env_str.split("=")
        if len(var_parts) != 2 or not var_parts[0]:
            raise Exception(
                f"Invalid format of environment variable {env_str}, "
                f"please ensure that the variable is in the format e.g. foo=bar."
            )
        var_name, value = var_parts

        if var_name in env_vars_dict:
            raise Exception(f"Environment variable '{var_name}' is duplicated. Please only include it once.")

        if not re.match(r"[0-9a-zA-Z_]+", var_name):
            raise ValueError(
                f"Environment variable '{var_name}' is not a valid name. It is only allowed to contain digits 0-9, "
                f"letters A-Z, a-z and _ (underscore)."
            )

        env_vars_dict[var_name] = value
    return env_vars_dict


def _is_url(id: Optional[str]) -> bool:
    if isinstance(id, str) and (id.startswith("https://") or id.startswith("http://")):
        return True
    return False


def _get_metadata_from_openapi(paths: Dict, path: str):
    parameters = paths[path]["post"].get("parameters", {})
    tag = paths[path]["post"].get("tags", [None])[0]
    cls_path = paths[path]["post"].get("cls_path", None)
    cls_name = paths[path]["post"].get("cls_name", None)
    description = paths[path]["post"].get("description", None)
    requirements = paths[path]["post"].get("requirements", None)

    metadata = {"tag": tag, "parameters": {}}

    if cls_path:
        metadata["cls_path"] = cls_path

    if cls_name:
        metadata["cls_name"] = cls_name

    if description:
        metadata["description"] = description

    if description:
        metadata["requirements"] = requirements

    if not parameters:
        return metadata

    metadata["parameters"].update({d["name"]: d["schema"]["type"] for d in parameters})
    return metadata


def _extract_command_from_openapi(openapi_resp: Dict) -> Dict[str, Dict[str, str]]:
    command_paths = [p for p in openapi_resp["paths"] if p.startswith("/command/")]
    return {p.replace("/command/", ""): _get_metadata_from_openapi(openapi_resp["paths"], p) for p in command_paths}


class _LightningAppOpenAPIRetriever:
    def __init__(
        self,
        app_id_or_name_or_url: Optional[str],
        use_cache: bool = False,
    ):
        """This class encapsulates the logic to collect the openapi.json file from the app to use the CLI Commands.

        Arguments:
            app_id_or_name_or_url: An identified for the app.
            use_cache: Whether to load the openapi spec from the cache.
        """
        self.app_id_or_name_or_url = app_id_or_name_or_url
        self.url = None
        self.openapi = None
        self.api_commands = None
        self.app_id = None
        self.app_name = None
        home = os.path.expanduser("~")
        if use_cache:
            cache_openapi = os.path.join(home, ".lightning", "lightning_connection", "commands", "openapi.json")
            if os.path.exists(cache_openapi):
                with open(cache_openapi) as f:
                    self.openapi = json.load(f)
                self.api_commands = _extract_command_from_openapi(self.openapi)

        if not self.api_commands:
            self._collect_open_api_json()
            if self.openapi:
                self.api_commands = _extract_command_from_openapi(self.openapi)

    def is_alive(self) -> bool:
        """Returns whether the Lightning App Rest API is available."""
        if self.url is None:
            self._maybe_find_url()
        if self.url is None:
            return False
        resp = requests.get(self.url)
        return resp.status_code == 200

    def _maybe_find_url(self):
        """Tries to resolve the app url from the provided `app_id_or_name_or_url`."""
        if _is_url(self.app_id_or_name_or_url):
            self.url = self.app_id_or_name_or_url
            assert self.url
            return

        if self.app_id_or_name_or_url is None:
            url = f"http://localhost:{APP_SERVER_PORT}"
            resp = requests.get(f"{self.url}/openapi.json")
            if resp.status_code == 200:
                self.url = url
                return

        app = self._maybe_find_matching_cloud_app()
        if app:
            self.url = app.status.url

    def _maybe_find_matching_cloud_app(self):
        """Tries to resolve the app url from the provided `app_id_or_name_or_url`."""
        client = LightningClient()
        project = _get_project(client)
        list_apps = client.lightningapp_instance_service_list_lightningapp_instances(project_id=project.project_id)

        app_names = [lightningapp.name for lightningapp in list_apps.lightningapps]

        if not self.app_id_or_name_or_url:
            print(f"ERROR: Provide an application name, id or url with --app_id=X. Found {app_names}")
            sys.exit(0)

        for app in list_apps.lightningapps:
            if app.id == self.app_id_or_name_or_url or app.name == self.app_id_or_name_or_url:
                if app.status.url == "":
                    print("The application is starting. Try in a few moments.")
                    sys.exit(0)
                return app

    def _collect_open_api_json(self):
        """This function is used to retrieve the current url associated with an id."""

        if _is_url(self.app_id_or_name_or_url):
            self.url = self.app_id_or_name_or_url
            assert self.url
            resp = requests.get(self.url + "/openapi.json")
            if resp.status_code != 200:
                print(f"ERROR: The server didn't process the request properly. Found {resp.json()}")
                sys.exit(0)
            self.openapi = resp.json()
            return

        # 2: If no identifier has been provided, evaluate the local application
        if self.app_id_or_name_or_url is None:
            try:
                self.url = f"http://localhost:{APP_SERVER_PORT}"
                resp = requests.get(f"{self.url}/openapi.json")
                if resp.status_code != 200:
                    raise Exception(f"The server didn't process the request properly. Found {resp.json()}")
                self.openapi = resp.json()
            except requests.exceptions.ConnectionError:
                pass

        # 3: If an identified was provided or the local evaluation has failed, evaluate the cloud.
        else:
            app = self._maybe_find_matching_cloud_app()
            if app:
                if app.status.url == "":
                    raise Exception("The application is starting. Try in a few moments.")
                resp = requests.get(app.status.url + "/openapi.json")
                if resp.status_code != 200:
                    raise Exception(
                        "The server didn't process the request properly. " "Try once your application is ready."
                    )
                self.url = app.status.url
                self.openapi = resp.json()
                self.app_id = app.id
                self.app_name = app.name


def _arrow_time_callback(
    _ctx: "click.core.Context", _param: "click.core.Option", value: str, arw_now=arrow.utcnow()
) -> arrow.Arrow:
    try:
        return arw_now.dehumanize(value)
    except ValueError:
        try:
            return arrow.get(value)
        except (ValueError, TypeError):
            raise click.ClickException(f"cannot parse time {value}")


def _is_valid_release(release):
    version, release = release
    version = packaging.version.parse(version)
    if any(r["yanked"] for r in release) or version.is_devrelease or version.is_prerelease:
        return False
    return True


@functools.lru_cache(maxsize=1)
def _get_newer_version() -> Optional[str]:
    """Check PyPI for newer versions of ``lightning``, returning the newest version if different from the current
    or ``None`` otherwise."""
    if packaging.version.parse(__version__).is_prerelease:
        return None
    try:
        response = requests.get(f"https://pypi.org/pypi/{__package_name__}/json")
        releases = response.json()["releases"]
        if __version__ not in releases:
            # Always return None if not installed from PyPI (e.g. dev versions)
            return None
        releases = {version: release for version, release in filter(_is_valid_release, releases.items())}
        sorted_releases = sorted(
            releases.items(), key=lambda release: release[1][0]["upload_time_iso_8601"], reverse=True
        )
        latest_version = sorted_releases[0][0]
        return None if __version__ == latest_version else latest_version
    except Exception:
        # Return None if any exception occurs
        return "err"


def _redirect_command(executable: str):
    """Redirect the current lightning CLI call to the given executable."""
    subprocess.run(
        [executable, "-m", "lightning"] + sys.argv[1:],
        env=os.environ,
    )

    sys.exit()


def _check_version_and_upgrade():
    """Checks that the current version of ``lightning`` is the latest on PyPI.

    If not, prompt the user to upgrade ``lightning`` for them and re-run the current call in the new version.
    """
    new_version = _get_newer_version()
    if new_version:
        prompt = f"A newer version of {__package_name__} is available ({new_version}). Would you like to upgrade?"

        if click.confirm(prompt, default=True):
            command = f"pip install --upgrade {__package_name__}"

            logger.info(f"⚡ RUN: {command}")

            # Upgrade
            subprocess.run(
                [sys.executable, "-m"] + command.split(" "),
                check=True,
            )

            # Re-launch
            _redirect_command(sys.executable)
    return


def _check_environment_and_redirect():
    """Checks that the current ``sys.executable`` is the same as the executable resolved from the current
    environment.

    If not, this utility tries to redirect the ``lightning`` call to the environment executable (prompting the user to
    install lightning for them there if needed).
    """
    env_executable = os.path.realpath(shutil.which("python"))
    sys_executable = os.path.realpath(sys.executable)

    # on windows, the extension might be different, where one uses `.EXE` and the other `.exe`
    if env_executable.lower() != sys_executable.lower():
        logger.info(
            "Lightning is running from outside your current environment. Switching to your current environment."
        )

        process = subprocess.run(
            [env_executable, "-m", "lightning", "--version"],
            capture_output=True,
            text=True,
        )

        if "No module named lightning" in process.stderr:
            prompt = f"The {__package_name__} package is not installed. Would you like to install it? [Y/n (exit)]"

            if click.confirm(prompt, default=True, show_default=False):
                command = f"pip install {__package_name__}"

                logger.info(f"⚡ RUN: {command}")

                subprocess.run(
                    [env_executable, "-m"] + command.split(" "),
                    check=True,
                )
            else:
                sys.exit()

        _redirect_command(env_executable)
    return
